Dynamic Limit

Sometimes it is useful to change the limit per page dynamically say with a drop down.
That is where forLimitChange() becomes useful as it will return the correct start
value after a limit change which will allow everything to line up correctly and the user
to be on a correct page. This will also make sure the database is set to return the
correct starting record as well.

Contributions

Any pull requests are more than welcome. Please make your changes in your own branch, make sure the current specs in angular-pagination.spec.js are passing (Jasmine/Karma) and update/add tests if necessary.